Why did early Sufi authors write handbooks explaining Sufi beliefs?

Early Sufi authors began writing systematic handbooks in the 10th century primarily to address and soothe the growing suspicions held by the orthodox religious community. By composing these compendiums, authors such as Abū Ṭālib Makkī, Sarrāj, and Kalābādhī sought to defend Sufism and demonstrate its compatibility with Islamic law and theology.12

These works served to formalize the tenets of the movement, which had previously been transmitted within small, private circles. While early Sufis had already produced spiritual writings, letters, and meditations, the creation of these handbooks marked a shift toward documenting the path in a way that could be scrutinized and validated by the broader Muslim society.21